Method and device for coding a magnetically codable card

The subject of the invention is a method for coding a magnetically codable card, in particular an identity card, cheque card, credit card or authorisation card, with a magnetic strip containing at least one recording track. Items of information are written into the recording tracks by means of a write head as sequences of characters or bits and are read out by means of a read head or are read out and/or overwritten or erased by means of a combined read/write head. To fix a certain period of validity of the magnetically codable card, any desired number of bits or freely selectable characters are written by means of the write head in at least part of a recording track. To extend the period of validity of the magnetically codable card, some of the written-in bits or freely selectable characters are overwritten or erased.